Terpolymer latex and process



United States Patent Otfice 3,442,844 TERPOLYMER LATEX AND PROCESSRobert Thomas Bouchard, Gardner, Jack Dickstein, Leominster, and DonaldEugene Dean, Fitchburg, Mass.,

assignors to The Borden Company, New York, N.Y.,

a corporation of New Jersey No Drawing. Filed Feb. 10, 1966, Ser. No.526,381

Int. Cl. C08f 15/40; C09d /02 US. Cl. 26029.6 10 Claims ABSTRACT OF THEDISCLOSURE This invention relates to layered terpolymers of vinylacetate. More particularly, the invention relates to layered terpolymersof vinyl acetate which impart improved scrub resistance to latex basepaints and will be described in connection therewith.

Latex paints have been prepared from layered terpolymers wherein eachlayer has approximately the same proportion of monomers therein. Theselatex paints, although satisfactory for most purposes, suffer from alimitation of having reduced scrub resistance. Such scrub resistancetests are hereinafter described in connection with this invention.

Briefly stated, the instant invention provides a latex base paint havingsuperior scrub resistance at room and reduced temperatures.

.The present invention comprises a unique polymerization method forpreparing the terpolymer, said terpolymer, and latex base paints madewith said terpolymer wherein vinyl acetate comprises the major monomerproportion of the terpolymer.

The terpolymer is found to have the superior scrub resistance propertieswhen made as a layered particle having the outer layer enriched inacrylate ester content. The ester provides additional softness in theouter layer and the desired hardness in the inner or core layer of theparticle. The advantageous results achieved by a layered particle ofthis type are shown in the table.

As to materials, the terpolymer includes vinyl acetate in majorproportions for which we know of no substitute.

The comonomers with vinyl acetate are dialkyl esters of alpha-betaunsaturated dicarboxylic acids, as for example, C C dialkyl substitutedC -C alpha-beta unsaturated dicarboxylic acids. The alpha-betaunsaturation is a polymerizable ethenoid double bond. The othercomonomer with vinyl acetate are C -C alkyl ester of an acrylic ormethacrylic acid.

Specific examples of the dialkyl moiety of the esters of thedicarboxylic acids include dimethyl, diethyl, dibutyl, dihexyl, dioctyl,didecyl and combinations thereof, as for example, ethyl-octyl. Thedicarboxylic acid component of the 'diester is typified as maleic,fumaric, itaconic, citraconic, mesaconic, glutaconic, and the likeacids.

Preferred are the dialkyl maleates and especially diootyl maleatebecause of its integral plasticizing ability in the terpolymer. It isunderstood that this preferred monomeric component may be mixed dialkylesters of said dicarboxylic acid.

3,442,844 Patented May 6, 1969 Examples of the alkyl acrylates includemethyl, isopropyl, 2-ethylhexyl, butyl and octyl esters of acrylic andmethacrylic acid.

Other materials which can be added as desired and as known in thepolymerization art are, for example, thickeners', emulsifiers,defoamers, water, catalysts, etc. The preferred catalyst of ethenoidbond polymerization is the peroxy type catalyst, as for example,potassium persulfate, azo-bis-isobutyronitrile, hydrogen peroxide,benzoyl peroxide, bis-2-4-dichlorobenzoyl chloride, di-l-naphthoylperoxide, and t-butyl hydro-peroxide, alone or in combination.

Examples of the other additives include hydroxy ethylcellulose as athickener, ethoxylated sodium lauryl sulfate as emulsifier, mixedhydrocarbons containing less than 1% silicone as a defoamer, and othermaterials useful for associated purposes.

In the process of this invention the monomeric components are preparedin separate mixtures as briefly described. .Into the first portion(portion I) is mixed approximately A of the total vinyl acetate,approximately /2 of the total dialkyl ester of dicarboxylic acid, andapproximately 6 of the total acrylate ester. The second portion (portionII) is a mixture of the remaining monomers.

Between about 1-50% of the total monomer weight is added to the reactionvessel from portion 1 together with catalyst i the first addition step.Other additives can also be "included therein. After polymerization ofthis portion, the remaining part of portion 1 is added to the reactionvessel followed by the total of portion II together with the remainderof the catalyst. Polymerization proceeds until the vapor pressuresubstantially drops and maintains a constant level thereby indicatingsubstantially complete polymerization.

As to proportions, the following tables set forth the illustrated andrecommended ranges of proportions. It is to be understood that theillustrated range is typical of the proportions of the invention and therecommended range is within the optimum or preferred range ofproportions.

Into 38 grams of water at room temperature containing hydroxy-ethylcellulose (.5 grams, thickener), ethoxylated sodium lauryl sulfate (2.5grams, emulsifier), and mixed hydrocarbons containing less than 1%silicone 3 (.003 gram, defoamer) was added 5.4 grams of monomers fromportion 1, in the proportions shown. The monomers were prepared in twoportions in the gram quantities shown:

face. The number of scrubs required to obtain film failure was noted ata particular temperature.

TABLE IV Average number of scrubs to failure 5 Fg i a s; gg ig dmgTemperature, F. Example I Example V 199 162 20 1i%ty1Zis::::::::: 31232? 33 141 193 25 2-Ethy1 hexyl aerylate 1- 8 3. 7

The higher number of scrubs required confirms the tougher paint productmade. 102 31:;fippfb i i a ly a giair if 53.5 grams of whlch It will beunderstood that it is intended to cover all Potassium persulfate (.12gram, catalyst) in a water changes fi modlficanons of the examPles of ii solution was added to the monomer vessel and the system harem chosenfor i purposa of lnuitiatlon whlch heated to reflux. When the batchreached 82 C., the redo not.const.ltute departures from the Spmt andScope mainder of portion I was slowly added, followed by porof the i ftion II. The total time for adding the remainder of por- We clalm' tionI and portion II was about 3 hours. Additional cata- Process for makmglayered terpolymers whlch lyst (.13 gram), was also added. At the end ofthe last comprises: addition period, the batch was heated to about 92-93C. (1) formmg. monomimc mlxture poiuons and held for about 30 minutesuntil the reflux subsided. each Conslstmg essentially of a vlnylacetate, a dialk yl The unreacted monomers were removed by vapor stripester of an alpha-beta unsaturated dicarboxylic acid, ping at 90-92 C.for an additional 15 minutes prior to and u a yiacryhc ester; cooling.Additional catalyst may optionally be added to (2) admlxmg aqueousmedlum: the batch during the stripping step to aid in eliminating (a)from about 1% to about 50% by Yvelght free monomer. The latex was about55% solids. of total monomers taken from a first Porno of monomers, saidtotal monomers consisting es- Example H sentially of, in weightproportion for 100 parts The procedure of Example I is repeated exceptthat of total.monomer.s m sald first porno; vmyl the dioctyl maleate isreplaced separately and in turn by aFetate propomon of between 50*90Pin-ts; the dialkyl esters of alpha-beta unsaturated dicarboxylicdlalky} F of alphii'beta unsaturated dlcar' acids and in proportionsherein disclosed. boxyhc and m liropomqn of 5 45 parts;

and, alkyl acrylic ester in proportion of between ple III 3-20 parts;said first portion being a mixture of The procedure of Example I isrepeated except that the Said Vinyl acetate in Weight P P P of 2-ethylhexyl acrylate is replaced separately and in turn f of the totffill P PPP of said by the alkyl esters of acrylic and methacrylic acid and inVlnyl acetate In h portions; said dialkyl ester proportions hereindisclosed 40 of alpha-beta unsaturated dlcarboxyhc acid in weightproportion of between 05-70% of the Ple IV total proportion of saiddialkyl ester in both The procedure of Example I is repeated except thatthe P and, Said alkyl acrylic ester in Weight proportions of theportions shown in that example are proportfon of befween 05-40% of thetotal changed as follows. proportion of said alkylacrylic ester in bothportions; and, PortionI Portion II catalyst of Polymerization;

(g (3) heating said admixture to refiux; vinylacetate 19 26 (4) slowlyadmixing into said admixture, the balance g ggg gi gg Z 2 of said firstportion together with catalyst of polymerlzatlon;

30 38 (5) slowly admixing the second portion of monomers, together withcatalyst of polymerization, said second and the first addition ofportion I is 20% of the total portion being a mixture of remainingmonomers and monomer weight, namely, 13.6 grams. The other masaid alkylacrylic ester being present in a proporterials are adjusted inproportion to the monomers used. tion, based on total monomers presentin said first Example v and second portions, greater than in said firstportion; and,

Th procedure of Example 1 was t d except h (6) heating said totalmonomers admixture at reflux. all the monomers were mixed together andaddition was The Process of claim 1, wherein the Weight P P made asdescribed, namely, 10% of the mixed monomers tron of said first portionis between 540% of said total were added initially, followed by theremaining 90% over monomers a 3-hour period. This Example is not part ofthe instant The Process of clalm f f said dialkyl ester invention, butis used to contrast the improved properties 18 sel.eted from the groupconslstmg of dialkyl of the products made with the process of thisinvention. ig g alpha'beta unsaturated dlcarboxyhc Example VI 4. Theprocess of claim 1, wherein said alkyl acrylic The polymers of ExamplesI and V were made into a ester 1s selected from the group consisting ofC -C latex paint by blending 145 grams of each of said latices alkylesters of acryhc f methacrylic with 1008 grams respectively of aninterior flat paint base The process of Wherem .Sald dialkyl ester usingStandard manufacturing techniques. fie 1(3311(1)catg rlyirgiaeleate andsaid alkyl acryllc ester 1s 2-ethyl The latex base paints were drawndown as a film on an adhering surface such as plaster board. A Gardner gg iggii ig 32 12 3 Z2 25: f ig fi fis Si g scrub machine was used torepeatedly scrub the dried suri f between 25 55% of the total proportionof s 5 6 vinyl acetate; said dioctyl maleate in weight proportionReferences Cited of between 25-55% of the total proportion of saiddioctyl UNITED STATES PATENTS maleate; and, said 2-ethy1 hexyl acrylatein 'weight pro- 3 275 589 9/1966 Alexander et a1.

portion of between 520% of the total proportion of 2,570,253 10/1951Lungquist 0 2 said 2-ethyl hexyl acrylate. 5 2,795,564 6/1957 Conn et a126029.6 7. The terpolymer made as in the process of claim 1. 3,070,56112/ 1962 Hager et al. 260-296 8. The terpolymer made as in the processof claim 6. 3,231,534 1/1966 ad et a 26029.6 9. A Water based latexpaint including the terpolyrner made as in the process of claim 1-SAMUEL H. BLECH, Przmary Exammer.

10. A (water based latex paint including the terpolymer ROBERTSAssistant Examinermade as in the process of claim 6. Us' Cl. X-R!

